Boiler for the production of steam or for the evaporation of solutions.



H. SCHEFTLEIN.

BOILER FOR THE PRODUCTION OF STEAM OR FOR THE EVAPORATION 0F SOLUTIONS.

APPLICATION FILED NOV. I, 19I3.

Iutvnted Apr. 25, 1916 3 SHEE[SSHEET1 H. SCHEFTLEIN. I

BOILER FOR THE PRODUCHON 0F STEAM OR FOR THE EVAPORATION 0F SOLUTIONS.

APPLICATION FILED NOV. 1. 191a.

l.180,545. Patented Apr. 1916.

3 SHEETS-SHEET 2- 000000000 .ooooqoooo H. SCHEFTLEIN. BOILER FOR THEPRODUCTION OF STEAM OR FOR THE EVAPORATION 0F SOLUTIONS.

APPLICATION EILED NOV. 1. I913.

Patented Apr. 25, 1916.

3 SHEETSSHEET 3.

. HANS SCHEFTLEIN, OF CHRISTIANIA, NORWAY, ASSIGNOIR. TO NORSK HYDRO-ELEKTRISK KVELSTOFAKTIESELSKAB, OF CHRISTIANIA, NORWAY.

BOILER FOR THE PRODUCTION OF STEAM 013, FOR THE EVAPORATION OFSOLUTIONS.

Application filed November 1,1913. Serial N 0. 798,714.

T (lug/01110777, it mdg concern Be it known that I, HANS SCHEFTLEIN, a

Specificationof Letters Eatent.

subject ofthe Emperor of Germany, residing at Christiania, Norway, haveinvented certain new and useful Improvements in Boilers for theProduction of Steam or for the ings, and to letters or figures ofreference marked thereon, which form a part of this specification.

In the production of nitrogen products by the combustion of the nitrogenof theatmosphere in an electric high voltage flame a comparatively s uall f portion only of the heat developed by t' elelectric energy isutilized for the oxidati n process. Attempts have therefore beerl madeto utilize by various means the heat of the gases issuing from 1 thenitrogen furnace for other technical pur- 25.

poses, for instance the gases have been conducted through boiler plants.The efliciency however of these systems for utilizing the heat, h/asnotbeen very great. On one hand the large-cost of installation and thelarge space required relatively to the heat obtained, and on the otherhand the large losses of heat caused by the passage of the gases throughpipes or channels, will act to reduce the productiveness of the plants.Said drawbacks will all be avoided, when according to the presentinvention, the nitrogen furnace is made integral with the boiler plantwhlch 1s possible when choosing suitable types of nitrogen furnace aswell as of boiler plant.

According to the present invention a ni trogen furnace of thetube-furnace type (i. e. the kind of high voltage furnace in which theflame is drawn out mainly by the action of a powerful current of air) ismounted in a boiler of a construction suitable for the purpose so thatthe nitrogen furnace will replace the fire-box. Thus all the heatdeveloped in the nitrogen furnace, and not-utilized for the oxidation ofthe nitrogen, will in this manner be supplied to the boiler without lossofheat.

According to the invention 'aboiler of a combined fiue and smoke. tubesystem is used the end walls C and D of the boiler.

Patented Apr. 25, 1916.

for this purpose, the vertical form of such a boiler being particularlysuitable.

The invention comprises not only the ,com bination of nitrogen furnaceand boiler re-.

ferred to, but also. the utilization of the boiler plant thus obtainedfor other purposes, thus in the first place as evaporators for thesolution (nitrate or nitrite solution, etc.) obtainedin the productionof the nitrogen products, which will be hereafter more particularlyexplained.

In the accompanying drawing are shown two forms of boiler plants inaccordance with the present invention.

Figures land 2 are a vertical sect-ion and a cross-section respectivelyof a boiler-construction -in which the nitrogen furnaces have beenplaced in position from below, Figs. 3 and 4 being correspondingsections of a boiler construction in which the nitrogen furnaces havebeen introduced from above.

In the former form the boiler has a flame tube A and smoke tubes Bmounted between Beneaththe tube wall C is formed a chamber F insulatedby chamotte E or the" like and connecting the flue A to the smoke tubesB.

At the top the gases pass from the smoke tube into a chamber G whencethey are conducted on to cooling apparatus, etc. Said chamber isseparated from the flue A by a chamber made of chamotte and which iscarried so far downward in an enlarged portion of the flue that itslower end will be a sufficient distance below the steam chamber of theboiler.

Mounted in the flue are three nitrogen fur-- naces K of a well-knowntype (in the longitudinal sectional view only one furnace has beenshown). The air enters at L and passes through the nitrogen furnaces inthe direction of the arrows.

M is the water-cooled portion of the fur- B nace. This cooling, which isused to avoid too great dissociation, however, may be effected by meansof a current of air accord which the gases pass in a downward direc-fflftion, the same will give off so much of their" heat as not to have anydestructive effect, in the chamber F, on the connection of the smoketubes with the boiler wall. At this point the gases willalso have atemperature rendering them fit for use in caloriferes for heating air tobe used in the concentration of nitric acid, for which reason anontlet Nis suitably provided for this purpose. at that point.

One or more furnaces may be provided in each flame flue the latterarrangement being of a certain advantage owing to the fact that thepeculiar pumping motion of the flame and the gases which takes place inthe nitrogen furnaces, will thereby be neutralized.

In the furnace according to Figs. 3 and l,

in which the reference characters correspond to those in Figs. 1 and 2,three flame fines A (each having one nitrogen furnace K introduced in itfrom above) and four groups of smoke tubes B, have been provided andarranged as shown in Fig. l. The smoketubes are not mounted in thebottom plate (Lof the boiler. but in plates R forming the end walls ofshorter flues S, which communicate through the chamber F with the fluesA and in which the gases are allowed to cool before reaching the smoketubes. Each flue A has an extension tube T into which the furnace isintroduced from above. 7

The arrangement of'one furnace in each fiue has the advantage thatclosing devices, of a simpleconstruction maybe provided so that eachfurnace may be separately dismounted without interfering with theoperation of the furnaces in the remaining flame flues.

The furnace is provided with an air preheating device which consists ofa plurality of concentric cylinders U arranged to form communicatingannular passages through which *air, supplied from the'inlet L. passesin the directions indicated by the arrows in Fig. 3, and is preheatedbefore it reaches the arc in the central flue k of the furnace throughwhich said air passes downward into the flame flue A. A cooling chrhnbcrM surrounds the lower portion of the central flue and is supplied with acooling medium which is circulated through pipes m.

A. sufficient distance below the top of the steam chamber of the boiler,the flame flue A. is contracted and the outer cylinder of the airpreheater is correspondingly enlarged so as to form a restricted annularpassage V. This passage serves to prevent the hot gases in the flue Afrom freely entering the upper part of the annular space J. formedbetween the tube T and the air preheater, as it is essential that saidannular space shall not be too highly heated where the tube T is notsurrounded'by water. K

As is already mentioned, the boiler systems herein referred to mayadvantageously be used for tivaporating a solutionobtained in.absorption processes conducted with liquids. For this purpose theboilers are used simultaneously for storing heat for heating and for thefirst step of the evaporation, the amounts of heat contained in thegases after the same have passed the boilers, are afterward used for thefinal concentration by means of known evaporating apparatus whichaccordingly are heated directly w'th the nitrous gases'obtained, insteadof with steam or direct firing.

By such an arrangement considerable ad vantages are obtained Theboilers, which in this construction will operate underatmosphericpressure or vacuum. require much less strength of construction, all thesteam pipes leading to the usual evaporating apparatus will be done awaywith, and the operation will be without all the dangers or ditl-'.iltics incident to the operation with high-pressure steam.

Besides great economy of the prime cost and of space. a far betterelliciency of the plant is obtained. eliminating all the losses whicharise in the absorption devices now in use owing to the fact that theheat of the gases is first utilized for the production of steam.

If it is desirable to drive part of'the tlllXll iary machinery (such ascompressors, pumps, or the like) by means of steam engines, part 'of theboilers may be constructed to produce to be reconcentrated. hot air oftemperatures up to about 500 C. and superhcatta'l steam of temperaturesup to above C. being advantageously used for said reconcentration.

I claim:

1. The combination of a steam boiler having a flame flue therein, asteam chamber surrounding the flue, a plurality of fire tubes extendingthrough said'chamber and communicating with the flue through one endthereof. and a high voltage are furnace arranged to discharge its gasesinto the flue at a distance from said end. whereby the temperature ofthe gases is lowered before entering the tubes.

The combination of a steam boile having a llamc ilue therein. a steamchamber surrouiulin-g the flue. a plurality of fire tubes extendingthrough said chamber and communicating with the flue through one endthereof, a high voltage arc furnace ar-' ranged to discharge its gasesinto the flue at a distance from said end, and a cooling device at thedischarge end of the furnace.

3. The combination of a steam boiler having a flame flue therein, asteam chamber surrounding the flue, a plurality of fire tubes extendingthrough said chamber, a high voltage arc furnace extending into the fluethrough the top of the boiler chamber, and short flues at the bottom ofthe latter communicating with the flame flue and fire tubes.

4. The combination of a steam boiler having a flame flue therein, asteam chamber surrounding the flue, a plurality of fire tubes extendingthrough said chamber and communicating with the flue through one endthereof, a high voltage are furnace arranged to discharge its gases intothe flue at a distance from said end, and means situated between theflue and pipes for drawing ofl' gases reduced in temperature.

5. The combination of a steam boiler having a flame flue therein, a highvoltage are furnace extending into the flue through the top thereof, asteam chamber surrounding the flue, short flues extending upward intothe steam chamberparallel to the flame flue and communicating with thelatter through a chamber situated below the steam chamber, fire tubescommunicating with the short flues and extending through the steamchamber, and means in the furnace for preheating air supplied theretobefore it reaches the arc.

6. The combinationof a steam boiler having a flame flue therein, a highvoltage are furnace extending into the flue through the top thereof, asteam chamber surrounding the flue, short flues extending upward intothe steam chamber parallel to the flame flue and communicating with thelatter through a chamber situated below the steam chamber, fire tubescommunicating with the short flues and extending through the steamchamber, means in the furnace for preheating air supplied thereto beforeit reaches the are, means to cool the gases issuing from the furnace,and means in the flame flue to' retard an upward movement of the gasestherein. 8. The combination of a steam boiler having a flame fluetherein, a high voltage are furnace extending into theflue through thetop thereof, a steam chamber surrounding the flue, short flues extendingupward into the steam chamber parallel to the flame flue andcommunicating withv the latter through a chamber situated below thesteam chamber, fire tubes communicating with the short flues andextending through the steam chamber, means in the furnace for preheatingair supplied thereto before it reaches the arc, means to cool the gasesissuing from the furnace, means in the flame flue to retard an upwardmovement of the gases therein, and means for-drawing ofli'

